20090314.ba v04_n254.bam.20090314 >From ???@??? Sat Mar 14 15:36:45 2009 -0500 Date: Sat, 14 Mar 2009 14:35:58 CST From: Old Tube Radios To: Old Tube Radios Subject: BOATANCHORS digest 4254 Message-Id: <20090314203600.6DCE510AF5F@srvr1.theporch.com> BOATANCHORS Digest 4254 Topics covered in this issue include: 1) Re: Recapping SX-100 by "Sandy" 2) Mea culpa by "Herbert M. Rosenthal" 3) Re: Recapping SX-100 by Garey Barrell 4) Re: Recapping SX-100 by "Arden Allen" 5) Loran C demise? by Dave or Debbie Metz 6) Signal generator by ray jefferson 7) Re: Loran C demise? by Jerry Proc 8) Re: Loran C demise? by "Arden Allen" 9) Loran C by "Herbert M. Rosenthal" 10) Re: Loran C by "Sandy" 11) Re: Loran C demise? by Jerry Proc 12) Need CQ article by "JAMES HANLON" 13) Re: Need CQ article by john 14) Re: [SPAM] Re: Loran C demise? by "Bob Moody" 15) OB2 function by john 16) Re: OB2 function by Chuck Grandgent ---------------------------------------------------------------------- Message-ID: From: "Sandy" To: Old Tube Radios Subject: Re: Recapping SX-100 Date: Thu, 12 Mar 2009 21:19:11 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit I would use disc ceramics where you can in the RF portions. I have, however recapped several receivers using some "bargain" 0.047mf 600 volt mylar caps I bought by the hundred CHEAP! (Wish I'd have bought a thousand of them!) I frequently used them in parallel to make larger caps from them where required. They were much more compact than the paper ones. I have a "stock" of disc ceramics like .001, .005, .01, and 0.02mf. at 500 or 1000 volts. The odd values are either in the junkbox or made up from multiple caps in parallel or series. DO NOT use the ceramic discs for resonant circuits! Stick with the little square brown dipped silver mica caps for that! Rarely do the true mica caps go bad. Beware of capacitors made by "Micamold" that look like p[ostage stamp micas but are really paper caps! They are horrible. They love to get leaky. Anyone who has dealt with "surplus" stuff can tell you about them. Especially SCR-522 conversions! 73, Sandy W5TVW ----- Original Message ----- From: "Arden Allen" To: "Old Tube Radios" Sent: Thursday, March 12, 2009 7:32 PM Subject: Re: Recapping SX-100 >> ......Is there any reason to NOT use disc ceramic caps to replace paper > caps >> in a receiver? ........ > > Not that I am aware of. Paper caps are not great performers > notwithstanding > what the audiophools contend. Ceramics make better bypass caps because > being smaller lead length to chassis can be shorter which reduces series > inductance. The somewhat higher dielectric absorption of general purpose > ceramics has little effect on audio coupling because of the miniscule > dynamic voltage gradient across the cap. Ceramics used in tone control > circuits may display some dielectric "euphony" but only a problem in > perfectionist grade audio gear. > > Arden Allen > KB6NAX > > Adopt a shelter dog, > save an innocent life, > and make a friend forever =:-) > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.237 / Virus Database: 270.11.12/1998 - Release Date: 03/12/09 18:23:00 ------------------------------ Message-ID: <49B9FB86.7040500@comcast.net> Date: Thu, 12 Mar 2009 23:21:58 -0700 From: "Herbert M. Rosenthal" MIME-Version: 1.0 To: Old Tube Radios Subject: Mea culpa Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sorry, guys-and thanks, Brian.... it IS 24/7/52 for the year's power KWH. No one is perfect. Herb ------------------------------ Message-ID: <49BA67CC.1090303@mindspring.com> Date: Fri, 13 Mar 2009 10:03:56 -0400 From: Garey Barrell MIME-Version: 1.0 To: Old Tube Radios Subject: Re: Recapping SX-100 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Arden Allen wrote: >> ......Is there any reason to NOT use disc ceramic caps to replace paper >> > caps > >> in a receiver? ........ >> > > Not that I am aware of. Paper caps are not great performers notwithstanding > what the audiophools contend. Ceramics make better bypass caps because > being smaller lead length to chassis can be shorter which reduces series > inductance. Thanks for all the replies.... I wonder... Hallicrafter's was the "Mad Man Muntz" of communications receivers when it came to parts quality. They had terrific designs, implemented with consumer radio parts. Compare the variable cap in the SX-100 with the one in the HQ-140 or the NC-300 for one good example. That said, I wonder why Hallicrafter's used "Black Beauty" paper caps for _everything_ when disc ceramics were available, at least in the values under 0.01uF, and were cheaper? Possibly just volume discounts? Minimizing number of different parts to stock/purchase? 73, Garey - K4OAH Glen Allen, VA ------------------------------ Message-ID: <003e01c9a419$651c7030$6f9e480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: Recapping SX-100 Date: Fri, 13 Mar 2009 13:11:25 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit > ....That said, I wonder why Hallicrafter's used "Black Beauty" paper caps > for _everything_ when disc ceramics were available, at least in the > values under 0.01uF, and were cheaper? Possibly just volume > discounts? Minimizing number of different parts to stock/purchase? Three reasons: 1) Economies of scale, i.e., paper caps were probably cheaper than ceramics when bought in high volume (10,000+). That comes from value engineering. 2) Engineers can be picky but designers are creatures of habit. One engineer mentions he likes paper caps and hates ceramics and paper caps become religion with designers while ceramics come from the devil. 3) Manufacturing managers and engineers get irate when they have to train assemblers new techniques to efficiently wire chassis. Ceramics break easily at the lead exits. Looks kinda sloppy and some would think it damaging to reliability (which is isn't). Smaller caps mean more wire in the air. So, keeping peace means sticking with tried and true. Yep, politics was alive and well at Halli's place too, no doubt. Purchasing never knows what's good and what's better. They just try to get good deals on stuff. Arden Allen KB6NAX Adopt a shelter dog, save an innocent life, and make a friend forever =:-) ------------------------------ Message-ID: <49BAE724.5000505@ntelos.net> Date: Fri, 13 Mar 2009 19:07:16 -0400 From: Dave or Debbie Metz MIME-Version: 1.0 To: Old Tube Radios Subject: Loran C demise? Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit I just got my latest ARRL email and there is an article stating that the Coast Guard is going to stop loran C in FY 2009. I thought there was a new loran C enhanced that was coming on board to give redundancy to the GPS system. Does anybody know anything about this new twist? If Jerry Proc is out there can you chime in? 73's dave ------------------------------ MIME-Version: 1.0 Date: Fri, 13 Mar 2009 17:06:09 -0700 Message-ID: Subject: Signal generator From: ray jefferson To: Old Tube Radios Content-Type: multipart/alternative; boundary=0016e64f51ae119584046508fcbe --0016e64f51ae119584046508fcbe Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Greetings: I am attempting to find info on an old signal generator I am working on. It has no AN/ number on it but has the following: TS413C/U and AF33(600)-21461. Looks to be about the fifties era. Any help will be appreciated as it is too good for the scrap heap. Ray Jefferson, W7FNI since.......1934 --0016e64f51ae119584046508fcbe Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * --0016e64f51ae119584046508fcbe-- ------------------------------ Message-ID: <125290.11978.qm@web90604.mail.mud.yahoo.com> Date: Fri, 13 Mar 2009 17:52:12 -0700 (PDT) From: Jerry Proc Subject: Re: Loran C demise? To: Old Tube Radios MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi Dave, Yes its true. Earlier this week I was contacted by the Captain of a charter= boat company in Florida. He asked me about my thoughts on how to keep the = Loran C system functioning. Not having a radionavigation background, I was= at a loss to figure out what can be done to ensure the survivability of Lo= ran C. Here in Canada, we would only be a very tiny voice in any potential = sea of objection. The closure of any existing nav system should be decided = by some type of input from its users, safety boards and not be dictated str= ictly by cost saving. My document on the future of Loran C can be found at: http://jproc.ca/hyperbolic/loran_c_future.html I also a bit on Enhanced Loran C at: http://jproc.ca/hyperbolic/loran_c_eloran.html **** Here is the letter the Captain wrote to his Congresswoman: An indispensable program that functions as an aid to maritime and aviation = navigation is at risk of termination according to the President=E2=80=99s p= roposed 2009 budget.=20 =E2=80=9C On February 26, 2009, the Office of Management and Budget (OMB) p= ublicly announced the President's Fiscal Year 2010 Budget. In the section f= or the Department of Homeland Security, the budget "supports the terminatio= n of outdated systems such as the terrestrial-based, long-range radio navig= ation (LOrAN-C) operated by the U.S. Coast Guard resulting in an offset of = $36 million in 2010 and $190 million over five years." For more information= on the proposed FY2010 Budget, visit the OMB website under President's Bud= get. =20 The Coast Guard will continue to operate the current Loran C system through= the end of FY2009 and is preparing detailed plans for implementing the FY2= 010 Budget.=E2=80=9D This program at risk is employed as a primary back up = navigational system to compliment current GPS capability (Global Positionin= g System). Commercial charter captains like myself and Merchant Marine navi= gators along with military and civilian navigators at sea and in the air va= lue having a redundant navigation capability in case of a failure of one of= these navigation systems. Can you imagine what it would be like to be with= out LORAN - C if someone were to jam the GPS signal close to the airports o= r seaports at San Francisco, Los Angeles, New York or Tampa? Due to the wea= kness of the satellite signals emanating from the orbiting vehicles which f= ix your location on GPS, anyone with a $30 Radio Shack jamming device and a= helium balloon to loft it into position can cause quite a mess of things. =20 That exact concern was expressed to me today by the U.S. Coast Guard=E2=80= =99s LORAN - C program director working at the Washington office. Another c= onsideration to evaluate into the economics of this is that there are costs= involved in dismantling and disposing of the numerous radio antennae and p= hysical plant infrastructures that constitute the LORAN C System. There wil= l also be job losses stemming from the product development and manufacturin= g side of this equation if LORAN - C is shut down.=20 In my estimation the loss of functional LORAN C will certainly not make for= a more safe and convenient navigational environment, nor will it result in= any savings to the taxpayer due to losses measured in lives and property d= amage incurred from increased crash and collision incidents. Please conside= r this issue to be one of great import and urgency and do your best to atte= nd to it. I have contacted Senator Martinez , Senator Nelson and House Repr= esentative Buchanan with the same request. Respectfully Captain xxxx xxxxx -- Regards, Jerry Proc E-mail: jerry7proc@yahoo.com --- On Fri, 3/13/09, Dave or Debbie Metz wrote: > From: Dave or Debbie Metz > Subject: Loran C demise? > To: "Old Tube Radios" > Received: Friday, March 13, 2009, 4:07 PM > I just got my latest ARRL email and there is an article > stating that the Coast Guard is going to stop loran C in FY > 2009. I thought there was a new loran C enhanced that was > coming on board to give redundancy to the GPS system. Does > anybody know anything about this new twist? If Jerry Proc > is out there can you chime in? >=20 > 73's > dave=0A=0A=0A ______________________________________________________= ____________=0ALooking for the perfect gift? Give the gift of Flickr! =0A= =0Ahttp://www.flickr.com/gift/ ------------------------------ Message-ID: <002001c9a45b$8c86e640$609d480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: Loran C demise? Date: Fri, 13 Mar 2009 21:11:54 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Yes its true. ...... Just to play devils advocate for a moment, isn't GPS a passive system like Loran C, i.e. the GPS navigation gear just listens to signals form several sattelites? How really effective would jamming be from a balloon hoisted Radio Shack toy? GPS is also a military system and must have a certain amount of robustness so that cruise missiles, etc. don't wonder off into someone else's back yard, ....no? Let's have some facts here. Doesn't seem to me an economic catastrophe to have a backup GPS receiver on board, especilly when you can get them at Radio Shack! And then, of course, the space aliens might decide to collect GPS satellites and take them to their home planet as vacation souvenirs..... Arden Allen KB6NAX Adopt a shelter dog, save an innocent life, and make a friend forever =:-) ------------------------------ Message-ID: <49BB57CD.8090603@comcast.net> Date: Sat, 14 Mar 2009 00:07:57 -0700 From: "Herbert M. Rosenthal" MIME-Version: 1.0 To: Old Tube Radios Subject: Loran C Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Believe it was near Tok, Alaska that made me drool everytime I passed the Loran transmitter site. The towers were about 200M high, which poses the question: will they be available for purchase when the system goes down? Can you imagine the fuss the neighbors would put up with one of these in your yard? :-) Two or more transmit -master- and transmit-slave stations generated line-of position that were quite accurate-sufficient for one to fly (or sail) (I taught Loran at Mather AFB in CA in the 1950s) around the coast of US. Not without its shortcomings, it was/is a good system, and I'll hate to see it go. Unlike GPS, it was not easy to jam. Herb W5AN Albuquerque ------------------------------ Message-ID: <97A78B94A066471C9B64C20396A71121@gateway> From: "Sandy" To: Old Tube Radios Subject: Re: Loran C Date: Sat, 14 Mar 2009 10:17:24 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit There is a site near New Orleans...actually west of town in the swamps by the Bonne Carre Spillway with a Loran C installation. The towers are not real high. I remember hearing the loran on the BC radio in the car when I passed the site on the elevated portion of I-10 west just before arriving at the LaPlace , LA exit. I'll have to checkout Virtual Earth to see if I can spot the site in the aerial photos. 73, Sandy W5TVW ----- Original Message ----- From: "Herbert M. Rosenthal" To: "Old Tube Radios" Sent: Saturday, March 14, 2009 2:07 AM Subject: Loran C > Believe it was near Tok, Alaska that made me drool everytime I passed > the Loran transmitter site. The towers were about 200M high, which poses > the question: will they be available for purchase when the system goes > down? Can you imagine the fuss the neighbors would put up with one of > these in your yard? :-) > > Two or more transmit -master- and transmit-slave stations generated > line-of position that were quite accurate-sufficient for one to fly (or > sail) (I taught Loran at Mather AFB in CA in the 1950s) around the coast > of US. Not without its shortcomings, it was/is a good system, and I'll > hate to see it go. Unlike GPS, it was not easy to jam. > > Herb W5AN > Albuquerque > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.237 / Virus Database: 270.11.13/2001 - Release Date: 03/14/09 06:54:00 ------------------------------ Message-ID: <622678.39653.qm@web90606.mail.mud.yahoo.com> Date: Sat, 14 Mar 2009 08:58:41 -0700 (PDT) From: Jerry Proc Subject: Re: Loran C demise? To: Old Tube Radios MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Hi Arden, At the 1997 Moscow air show, a jammer blocked GPS signals over a radius of 200 km. In this instance, I'm not sure if a backup GPS receiver would have done any good. Not sure how the military addresses this threat other than to revert to a backup system like Loran C. Does anyone in the group know? Commercial GPS users receive signals from the same satellites as the military, however the commercial signal is intentionally degraded to limit accuracy. This denies the "bad guys" the same level of accuracy as the military receives. I've heard, but can't confirm, that military accuracy can resolve down to 1 cm! In 2000 Bill Clinton passed an order which opened up GPS so that commerical users could avail themselves to more accuracy. Accuracy also depends on how many satellites in the constellation are turned up. The more comparisons the GPS receiver has, the more accurate the results. Not all the satellites in the constellation are always tured up, even for the military. A commercial GPS user once told me you can tell when a trouble spot is brewing somewhere in the world and US military forces are involved. All of a sudden GPS becomes more accurate as more satellites are turned up in the constellation. -- Regards, Jerry Proc E-mail: jerry7proc@yahoo.com --- On Fri, 3/13/09, Arden Allen wrote: > From: Arden Allen > Subject: Re: Loran C demise? > To: "Old Tube Radios" > Received: Friday, March 13, 2009, 9:11 PM > Yes its true. ...... > > Just to play devils advocate for a moment, isn't GPS a > passive system like > Loran C, i.e. the GPS navigation gear just listens to > signals form several > sattelites? How really effective would jamming be from a > balloon hoisted > Radio Shack toy? GPS is also a military system and must > have a certain > __________________________________________________________________ Yahoo! Canada Toolbar: Search from anywhere on the web, and bookmark your favourite sites. Download it now at http://ca.toolbar.yahoo.com. ------------------------------ Message-ID: From: "JAMES HANLON" To: Old Tube Radios Subject: Need CQ article Date: Sat, 14 Mar 2009 10:37:23 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0074_01C9A490.DC4512D0" This is a multi-part message in MIME format. ------=_NextPart_000_0074_01C9A490.DC4512D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Y'all, I'm in need of a copy of the CQ review on the B&W 6100. I'm told it = appeared in CQ for November of 1963, page 84. Any and all help would be = greatly appreciated. It's for an article on the 6100 for Electric = Radio. Thanks, Jim, W8KGI ------=_NextPart_000_0074_01C9A490.DC4512D0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------=_NextPart_000_0074_01C9A490.DC4512D0-- ------------------------------ Message-Id: <6.2.1.2.2.20090314130340.04e81d60@pop-server.nc.rr.com> Date: Sat, 14 Mar 2009 13:04:09 -0400 To: Old Tube Radios From: john Subject: Re: Need CQ article Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Found it....Oct 63 P49. Will get you the scan Jim John At 12:37 PM 3/14/2009, JAMES HANLON wrote: >Y'all, > >I'm in need of a copy of the CQ review on the B&W 6100. I'm told it >appeared in CQ for November of 1963, page 84. Any and all help would be >greatly appreciated. It's for an article on the 6100 for Electric Radio. > >Thanks, > >Jim, W8KGI ------------------------------ Message-ID: <3FBF48759475475C800BABD6C37E41C8@your5dfc0f230e> From: "Bob Moody" To: Old Tube Radios Subject: Re: [SPAM] Re: Loran C demise? Date: Sat, 14 Mar 2009 11:31:08 -0700 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="utf-8"; reply-type=original Content-Transfer-Encoding: 7bit Hello Arden: Yes, GPS is a passive system like LORAN, VOR, ADF and many others. GPS jamming does happen, and unfortunately is not too difficult to accomplish. No need to "launch it on a balloon". Just plant it on a hill, on a rooftop or in a vehicle. The satellites are thousands of miles away with a few watts, so a 5 watt jammer can be quite effective. Indeed, a 1 watt jammer can cause havoc for many miles. There are five GPS frequencies in the U.S. GPS system: L1 = 1,575.42 Mc. L2 = 1,227.60 Mc. L3 = 1,381.05 Mc L4 = 1,379.913 Mc. L5 = 1,176.45 Mc. Consumer grade GPS receivers use only L1 and can now give ~ 10 meter resolution since "selective availability" (SA) has been turned off. SA intentionally added error, or dither, to the signal degrading the position to ~ 100 meters resolution. Its purpose was to deny the enemy the best positional data. More advanced GPS units use two or more of the above frequencies improving positional accuracy and making intentional jamming more difficult. This is part of the "military robustness" you mentioned. Using a second single frequency consumer grade GPS won't help if the frequency is jammed. All single frequency GPS receivers in the area will be jammed. I doubt that Shack has a GPS jammer on the shelf. However they DO have the components to construct a crude jammer, and for that reason I have consistently encouraged aircraft owners to keep their ADF's against the day when GPS is compromised for whatever reason. If the GPS system goes down, and you find yourself in the clag or stuck on top, "antique ADF" can save your bacon. I spent half a career launching payloads on high altitude balloons and tracking them across the Country with light twins (Cessna 310). At various times we used LORAN, OMEGA, VOR, ADF, RADAR, Transponders, GPS, GMD, MK II Eyeballs and dead reckoning. GPS is by far the best system displaying not only position, but also course, speed altitude and time. GPS is now so good that it's easy to become complacent. But when it goes away - And it does - You better have a backup! Bob Moody K7IRK . ----- Original Message ----- From: "Arden Allen" To: "Old Tube Radios" Sent: Friday, March 13, 2009 9:11 PM Subject: [SPAM] Re: Loran C demise? > Yes its true. ...... > > Just to play devils advocate for a moment, isn't GPS a passive system like > Loran C, i.e. the GPS navigation gear just listens to signals form several > sattelites? How really effective would jamming be from a balloon hoisted > Radio Shack toy? GPS is also a military system and must have a certain > amount of robustness so that cruise missiles, etc. don't wonder off into > someone else's back yard, ....no? Let's have some facts here. Doesn't > seem > to me an economic catastrophe to have a backup GPS receiver on board, > especilly when you can get them at Radio Shack! > > And then, of course, the space aliens might decide to collect GPS > satellites > and take them to their home planet as vacation souvenirs..... > > Arden Allen > KB6NAX > > Adopt a shelter dog, > save an innocent life, > and make a friend forever =:-) > > ------------------------------ Message-Id: <6.2.1.2.2.20090314161241.04edae40@pop-server.nc.rr.com> Date: Sat, 14 Mar 2009 16:31:43 -0400 To: Old Tube Radios From: john Subject: OB2 function Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed I'm working on a transmitter that has a series stack of 3 OB2 VR tubes. When the (newly repaired ) Amperite TD relay pulls in , it applies primary voltage through another relay to a number of transformers...one being the plate transformer. There's a voltage divider off the filtered B+ that is applied across the string of OB2's to generate the regulated 320V from these 3 tubes When primary voltage is applied, the tube at the top of this string glows quite brightly...MUCH more so than the others in the string. The circuit is shown at: http://www.k5mo.com/trix.jpg and the tube in question is V20. My question is, what is the normal brilliance of these tubes when they're doing their thing. At this point there *should* be little load on this line. Should they all light at roughly the same brilliance? Thanks, John K5MO ------------------------------ MIME-Version: 1.0 Date: Sat, 14 Mar 2009 16:35:46 -0400 Message-ID: Subject: Re: OB2 function From: Chuck Grandgent To: Old Tube Radios Cc: Old Tube Radios Content-Type: multipart/alternative; boundary=001636e0b473819f9f04651a290a --001636e0b473819f9f04651a290a Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit I hope there's some resistors across each OB2 to even things up. What's the measured voltage across each one ? Also, a symptom of a 'bad" OB2 can be that it glows like that. Chuck, K1OM On Sat, Mar 14, 2009 at 4:31 PM, john wrote: > I'm working on a transmitter that has a series stack of 3 OB2 VR > tubes. When the (newly repaired ) Amperite TD relay pulls in , it applies > primary voltage through another relay to a number of transformers...one > being the plate transformer. There's a voltage divider off the filtered B+ > that is applied across the string of OB2's to generate the regulated 320V > from these 3 tubes > > When primary voltage is applied, the tube at the top of this string > glows quite brightly...MUCH more so than the others in the string. > > The circuit is shown at: http://www.k5mo.com/trix.jpg and the tube in > question is V20. > > > My question is, what is the normal brilliance of these tubes when > they're doing their thing. At this point there *should* be little load on > this line. Should they all light at roughly the same brilliance? > > > Thanks, John K5MO > > --001636e0b473819f9f04651a290a Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * --001636e0b473819f9f04651a290a-- ------------------------------ End of BOATANCHORS Digest 4254 ******************************